Aryl 4-piperidyl ketone derivatives

ABSTRACT

NOVEL COMPOUNDS HAVING THE FORMULA   4-(((R)N-PHENYL)-CO-)PIPERIDINE   WHEREIN N IS A POSITIVE WHOLE INTEGER OF FROM 1 TO 3; R REPRESENTS PHENYL, A STRAIGHT OR BRANCHED ALKYL CHAIN OF FROM 1 TO 4 CARBON ATOMS ATTACHED TO THE PHENYL RING AT THE ORTHO, META, OR PARA POSITIONS, OR A DIFUNCTIONAL 1,4-BUTADIENYLENE MOIETY WHICH TOGETHER WITH THE PHENYL RING FORMS A NAPHTHYL RING WITH THE PROVISO THAT WHEN R REPRESENTS A DIFUNCTIONAL 1,4-BUTADIENYLENE MOIETY, N IS EQUAL TO 1; OR PHARMACEUTICALLY ACCEPTABLE ACID SALTS THEREOF, ARE USEFUL AS ANALGESIC AND AS ANTICOAGULANT AGENTS.

3,795,677 ARYL 4-PIPERIDYL KETONE DERIVATIVES Albert A. Carr and Donald R. Meyer, Cincinnati, Ohio, assignors to Richardson-Merrell Inc., New York, N.Y. No Drawing. Filed Nov. 9, 1971, Ser. No. 197,116

Int. Cl. C0711 29/20 .1 US. Cl. 260293.62 3 Claims ABSTRACT OF THE DISCLOSURE Novel compounds having the formula wherein n is a positive whole integer of from 1 to 3; R represents phenyl, a straight or branched alkyl chain of from 1 to 4 carbon atoms attached to the phenyl ring at the ortho, meta, or para positions, or a difunctional 1,4-butadienylene moiety which together with the phenyl ring forms a naphthyl ring with the proviso that when -R represents a difunctional 1,4-butadienylene moiety, n is equal to 1; or pharmaceutically acceptable acid salts thereof, are useful as analgesic and as anticoagulant agents.

FIELD OF INVENTION This invention relates to novel aryl 4-piperidyl ketone derivatives which are useful as analgesic and anticoagulant agents.

SUMMARY OF THE INVENTION The novel aryl 4-piperidyl ketone derivatives of this invention which are useful as analgesics and anticoagulants are represented by the following formula Formula I wherein n is a positive whole integer of from 1 to 3; R represents phenyl, a straight or branched alkyl chain of from 1 to 4 carbon atoms attached to the phenyl ring at, the ortho, meta, or para positions, or a difunctional 1,4-butadienylene moiety which together with the phenyl ring forms a naphthyl ring with the proviso that when R represents a difunctional 1,4-butadienylene moiety, n is United States Patent 3,795,677 Patented Mar. 5, 1974 "Lee equal to 1; or pharmaceutically acceptable acid addition salts thereof.

DETAILED DESCRIPTION OF THE INVENTION As examples of the substituents which 'R may represent in Formula I, there may be mentioned phenyl, a straight or branched alkyl chain of from 1 to 4 carbon atoms wherein al'kyl may be methyl, ethyl, propyl, isopropyl, butyl, isobutyl, or tertiary butyl attached to the phenyl ring at the ortho, meta or para position, or -R may represent a difunctional 1,4-butadienylene moiety which together with the phenyl ring forms an alpha or a beta naphthyl ring. It can be seen from the above Formula I that the compounds of this invention may be substituted phenyl-4- piperidyl ketone derivatives as represented by the following Formula II, alpha naphthyl 4-piperidyl ketone derivatives as represented by the following Formula III, or beta naphthyl 4-piperidyl ketone derivatives as represented by the following Formula IV.

N H Formula II N H Formula 111 N H Formula IV In the above Formula II, R represents phenyl or a straight or branched lower alkyl chain of from 1 to 4 carbon atoms and may be attached at the ortho, meta, or para positions of the phenyl ring, and m is a positive whole integer of from 1 to 3.

g Formula V wherein R is phenyl or a straight or branched lower alkyl chain of from 1 to 4 carbon atoms attached to the phenyl ring at the ortho, meta, or para positions.

Pharmaceutically acceptable acid addition salts of the base compounds of this invention are those of any suit able inorganic or organic acids. Suitable inorganic acids are, for example, hydrochloric, hydrobromic, sulfuric, phosphoric acids, and the like. Suitable organic acids are, for example, carboxylic acids, such as, for example, acetic, propionic, glycolic, lactic, pyruvic, malonic, succinic, fumaric, malic, tartaric, citric, ascorbic, maleic, hydroxymaleic, and dihydroxymaleic, benzoic, phenylacetic, 4- aminobenzoic, 4-hydroxybenzoic, anthranilic, cinnamic, salicylic, 4-aminosalicylic, 2-phenoxybenzoic, 2-acetoxybenzoic acid, and the like.

As examples of compounds of this invention there may be mentioned, for example, 4-piperidyl o-tolyl ketone, 4-piperidyl p-tolyl ketone, 4-piperidyl 2,3,4-trimethylphenyl ketone, 3,4-diethylphenyl 4-piperidyl ketone, 4-isopropylphenyl 4-piperidyl ketone, 4-tertiary-butylphenyl 4- piperidyl ketone, 3-ethylphenyl 4-piperidyl ketone, p-biphenylyl 4-piperidyl ketone, ot-naphthyl 4-piperidyl ketone, 4-piperidyl 3,4,5-tri-n-propylphenyl ketone, 2-isobutylphenyl 4-piperidyl ketone, fi-naphthyl 4-piperidyl ketone, 4-piperidyl 4-n-propylphenyl ketone, and the like.

The compounds of this invention are useful as analgesic agents and anticoagulants and can be used in the form of pharmaceutical preparations suitable for oral or parenteral administration. The quantity of compound in the unit dosage can vary over a wide range to provide from about 0.5 mg./kg. to about 50 mg./'kg. of body weight of the patient per dose to achieve the desired effect. The desired effect can be obtained by the consumption of from 5 to 300 mg. of the active ingredient taken 1 to 4 times daily. The compounds of this invention can be administered to warm blooded animals and particularly mammals.

The novel compounds, together with conventional pharmaceutical carriers can be employed in unit dosage forms such as solids, for example, tablets or capsules, or liquid solutions, suspensions, or elixirs for oral administration, or liquid solutions, suspensions, emulsions, and the like for parenteral use. The quantity of active ingredient in each dosage will generally differ depending on the type of unit dosage, the type of animal, and its weight. Thus, each dosage can contain from about 5 mg. to over 300 mg. of active ingredients in a significant quantity of pharmaceutical carrier. I

The utility of the compounds of this invention is illustrated by the following. The compound of Example 5 demonstrated in vitro a 100% inhibition of adenosine diphosphate induced platelet aggregation in human platelet rich plasma when 100 ,ug. of compound was added to each milliter of plasma. The compound of Example 4 when tested in mice in the standard hot plate test [N. B. Eddy and D. Leimbach, J. Pharm. Exp. Therap. 107, 385 (1953)] blocked reaction to the heat stimulus. This compound produced in ED of 33.5 mg./kg. in mice when administered orally.

The compounds of this invention may be administered alone or may be used in combination with other analgesics such as acetylsalicylic acid or p-ethoxyacetanilide with or without a stimulant such as wfieille to achieve the desired analgesic efiects. When a compound of this invention is used in combination with other analgesics, the ratio of the amount of compound to other analgesics may vary from about 1:1 to 1:10, preferably about 1:5. When a stimulant such as caffeine is used in combination with a compound of this invention and other analgesics the amount of stimulant used is about one-half as much as the amount of compound.

The compounds of this invention may be prepared by the Friedel-Crafts acylation of an appropriate aromatic compound as illustrated by the following:

0 ii-halo Lewis Acid h +L 1 (Rh =0 N H 1 2 Formula I In the above reaction, R and n have the meanings defined hereinbefore, and halo represents a halogen atom.

The above reaction may be carried out in a variety of solvents, such as, nitrobenzene, chlorinated hyrocarbons, such as, chloroform, tetrachloroethane, and the like, or an excess of the aromatic reactant, that is, Compound 1, and under catalysis of a variety of Lewis acids, such as, aluminum chloride, boron trifiuoride, hydrofluoric acid, stannic chloride, and the like. The amount of Lewis acid employed in the reaction varies from one to eight times, and is preferably three to four times more than the amount of acid chloride, Compound 2, employed on a molar basis. A preferred procedure is to combine the reactants, using an excess of the aromatic reactant as the solvent, in an ice bath and slowly adding an excess of aluminum chloride with stirring during which time the reaction temperature is maintained below 35 C. After the addition is complete the temperature of the reaction is elevated to from 25 to 0., preferably 50 to 70 C. for from 10 minutes to six hours, preferably 10 to 30 minutes. The reaction mixture is decomposed with water and ice then made strongly alkaline by treating with a 50% solution of sodium hydroxide with cooling. The reaction mixture is then extracted with a suitable solvent such as toluene, chloroform, chlorobenzene and the like. The organic extract is dried, filltered and concentrated to give a base of Formula I, which may be converted to an acid salt by generally known procedures.

The compounds of this invention may also be prepared by the oxidation of the corresponding a-(substituted)aryl-4-piperidine1nethanol derivatives with the appropriate chloride of oxidizing agents such as chromic acid, sodium dichromate, manganese dioxide, lead tetraacetate, and the like, with an appropriate solvent, such as, acetic acid, sulfuric acid, pyridine, and the like. The temperature of the reaction may vary from 0 to C., and it is preferred that the reaction be carried out at room temperature. Likewise the reaction time may vary from 10 minutes to one day depending upon the reaction conditions. Preferably the reaction time varies from one-half to one hour. The (it-(substituted)aryl-4-piperidinemethanol derivatives are obtained by catalytic reduction of the corresponding (substituted)aryl pyridine ketone or the corresponding a-(substituted)aryl 4 pyridinemethanol derivative. The (substituted)aryl pyridine ketones are prepared by the reaction of an appropriately substituted aryl Grignard reagent and isonicotinonitrile followed by hydrolysis of the resulting imine complex. The u-(substituted)aryl-4-pyridinemethanol derivatives are obtained by the reaction of an appropriately substituted Grignard reagent and pyridine-4-carboxaldehyde, subsequently decomposing the resulting complex with a saturated ammonium chloride solution. The following specific examples illustrate the invention.

EXAMPLE 1 p-Tert-butylphenyl 4-piperidyl ketone hydrochloride (A) To 450 ml. of thionyl chloride was added slowly and with stirring 129 g. (1.0 mole) of isonipecotic acid. The mixture was heated to 45 C. for minutes then the excess thionyl chloride was removed under vacuum at 50 C. The resulting oil was poured into ether, and a precipitate formed which was collected, washed with ether and vacuum dried to give 168 g. of isonipecotic acid chloride hydrochloride.

(B) To a mixture of 168 g. (0.915 mole) of isonipecotic acid chloride hydrochloride, 750 ml. of tetrachloroet'hane, 160 g. (1.19 moles) of tert-butylbenzene in an ice bath was slowly added with stirring 370 g. (2.78 moles) of aluminum chloride maintaining the reaction temperature below 25 C. The reaction mixture was slowly warmed to 65 C. for 10 minutes then decomposed by pouring the mixture into water and ice and cooling to C. The mixture was made strongly basic with 50% NaOH and chloroform was added. An equal volume of water was added, and a small amount of solid was filtered ofi. The organic phase was separated, and the aqueous layer was extracted with methylene chloride. The methylene chloride and chloroform extracts were combined and dried over anhydrous magnesium sulfate,

filtered, and treated with ethereal HCl and ether. The

EXAMPLE 2 2-naphthyl 4piperidyl ketone hydrochloride To a slurry of 99 g. of naphthalene (0.75 mole and 96 g. of isonipecotic acid chloride hydrochloride (0.5 mole) in tetrachloroethane was added over a period of ten minutes 200 g. (1.5 moles) of aluminum chloride. The reaction mixture was allowed to stand at room temperature for 10 minutes, then decomposed by pouring it over ice water, made basic with a 50% NaOH solution, and extracted with diethyl ether. The other layer was dried over magnesium sulfate, filtered, and treated with ethereal HCl. The resulting oil was dissolved in warmed methanol, treated with charcoal, filtered and diluted with butanone. The methanol was removed by distillation, adding more butanone as needed. The solution was cooled overnight, and the resulting solid filtered off and recrystallized from methanol-butanone to give the desired product, M.P. 251253 C.

EXAMPLE 3 Mesityl 4-piperidyl ketone hydrochloride To a stirred mixture of 20 g. (0.11 mole) of isonipecotic acid chloride hydrochloride in 50 ml. of mesitylene in an ice bath was added 60 g. (0.6 mole) of aluminum chloride. The reaction mixture was heated to 50 C. for one-half hour, decomposed by pouring onto ice, and made basic with a 50% NaOH solution. To the reaction mixture was added 2 ml. of toluene, and the organic layer was separated and dried over anhydrous magnesium sulfate. The mixture was filtered, treated with ethereal HCl, and the resulting precipitate was washed with dry diethyl ether and recrystallized several times from methanol-butanone to give the desired product, M.P. 295-296 C.

EXAMPLE 4 p-Isopropylphenyl 4-piperidyl ketone hydrochloride To a stirred mixture of 900 ml. (3.22 moles) of cumene and 368 g. (2.0 moles) of isonipecotic acid chloride hydrochloride was added with stirring on an ice bath 800 g. (6.0 moles) of aluminum chloride. The reaction mixture was heated to 50 C. for 10 minutes, cooled decomposed by pouring into ice-water and made basic with a 50% NaOH solution. The mixture was cooled and extracted into toluene. The toluene solution was dried over magnesium sulfate, filtered, and treated with ethereal HCl. The resulting precipitate was recrystallized from methanol-butanone to give the desired product, M.P. 245.5-246" C.

EXAMPLE 5 p-Biphenylyl 4-piperidyl ketone To a stirred mixture of 154 g. (1.0 mole) of biphenyl, 92 g. (0.5 mole) of isonipecotic acid chloride hydrochloride and 1 liter of methylene chloride in an ice bath was slowly added with stirring g. (1.12 moles) of aluminum chloride maintaining the reaction temperature at less than 19 C. An additional 500 ml. of methylene chloride was added, then the mixture was decomposed by pouring into water. The reaction mixture was treated with ethanol and chloroform until a small amount of solid went into solution. The organic layer was separated, filtered through celite, and the solvent was removed by heating, being gradually replaced with water. After cooling, the resulting solid was filtered off, washed with tol-. uene, dissolved in chloroform and ethanol and filtered through celite. The resulting product was isolated from this solution and washed with ether to yield p-biphenylyl 4-piperidyl ketone hydrochloride which was subsequently converted to the free base using methanol and sodium methoxide. The product was recrystallized from heptane to give p-biphenylyl 4-piperidyl ketone, M.P. 116.5- 119 C.

EXAMPLE 6 4-piperidyl p-tolyl ketone hydrochloride To a chilled and stirred mixture of 96.5 g. (0.4 mole) of a-(p-tolyl)-4-piperidinemethanol hydrochloride, 600 ml. of acetic acid, 40 ml. of 25% (v./v.) sulfuric acid and 72 ml. of water was added with stirring 26.5 g. (0.27 mole) of chromium trioxide in 30 ml. of acetic acid over a period of 1 /2 hours, during which time an additional 20 ml. of water was added. The mixture was stirred for half an hour at less than 9 C. The solvent was removed under vacuum, and the remaining residue was treated with excess sodium hydroxide then extracted successively with ether and chloroform. The combined extracts were washed with water, dried over anhydrous magnesium sulfate and filtered. To the filtrate was added chloroform and ethereal HCl. The resulting solid was filtered 01f and recrystallized from isopropyl alcohol and water to give the desired product, M.P. 274-277 C. (dec.).

EXAMPLE 7 4-piperidyl p-tolyl ketone hydrochloride To a stirred mixture of 147 g. (0.8 mole) of isonipecotic acid chloride hydrochloride and 300 m1. of dry toluene was added 320 g. (2.4 moles) of aluminum chloride while stirring in an ice bath. The reaction mixture was then warmed to 65 C. for 10 minutes, cooled and decomposed by pouring into an ice/water mixture. A solution of 800 ml. of 50% NaOH was added maintaining the temperature below 35 C. This material was extracted into toluene, dried over anhydrous magnesium sulfate, filtered through celite and treated with ethereal HCl. The resulting precipitate was washed with ether and recrystallized from methanol-butanone to give the desired product, M.P. 274-277 C. (dec.).

EXAMPLE 8 3,4-diethylpheny1 4-piperidyl ketone hydrochloride Following the procedure of Example 6 only substituting for a.- (p-tolyl)-4piperidinemethano1 hydrochloride an appropriate amount of a-(3,4-diethylphenyl)-4-piperidinemethanol hydrochloride the title compound isobtained.

EXAMPLE 9 As an example of a tablet formulation of an active compound of this invention the following may be mentioned:

Mg. per tablet (a) p-Tert-butylphenyl 4-piperidyl ketone hydrochloride 50.0 (b) Starch 40.0 (c) Lactose 160.0 (d) Magnesium stcarate 3.0

The granulation obtained upon mixing lactose with the active compound and part of the starch and granulated with starch paste is dried, screened and mixed with the magnesium stearate. The mixture is compressed into tablets weighing 253 mg. each.

EXAMPLE 10 (a) Mesityl 4-piperidyl ketone hydrochloride 50.0 (b) Acetylsalicylic acid 250.0 (c) Starch 40.0 (d) Lactose 120.0 (e) Magnesium stearate 5.0

The granulation obtained upon mixing lactose with mesityl 4-piperidyl ketone hydrochloride and part of the starch is granulated with starch paste, dried, screened and mixed with the acetylsalicylic acid and magnesium stearate. The mixture is compressed into tablets weighing 465.0 mg.

each.

We claim:

1. A 4-piperidyl ketone compound selected from the group consisting of p-biphenylyl 4-piperidyl ketone, a-naphthyl-4-piperidyl ketone or fi-naphthyl-4-piperidyl ketone or a pharmaceutically acceptabe acid addition salt thereof.

2. A compound of claim 1 which is 4-biphenylyl-4- piperidyl ketone or a pharmaceutically acceptable acid ad dition salt thereof.

3. A compound of claim 1 which is 5 naphthyl 4- piperidyl ketone or a pharmaceutically acceptable acid addition salt thereof.

References Cited UNITED STATES PATENTS 3,576,810 4/1971 Duncan et al. 260-294 HENRY R. JILES, Primary Examiner G. T. TODD, Assistant Examiner US. Cl. X.R. 

